Basically, I often come into discussions where I see discussions of history, and the refrain comes "x is an outdated and inaccurate notion going back to Victorian history!" ("Victorian" seems to carry approximately the same tone as "Hollywood" as an epithet impugning the historical truth of some idea.)
I see people criticizing the specific aspects of, e.g., what Gibbon wrote about the Byzantine Empire, but I don't usually see a general dismissal of, say, 18th century history in quite the same way.
Was Victorian history particularly prone to some types of errors? (Perhaps there were new methods of research coming to the fore (e.g., archaeology), but people hadn't yet realized their limitations, so new histories ended up making novel mistakes that older histories dependent on traditional archival research and written sources were less prone to?)
Or it just that history older than Victorian isn't a big problem (at least as far as being regarded as a reliable secondary source), so Victorian history is the oldest and least accurate history that's still widespread in mis-educating people?
I think it's more the latter. One of the key things is that history professionalized in the late nineteenth century as Britain and the US adopted the German university seminar model and the Rankean method became more prominent. The "amateur" histories which dominated the market were thus denigrated by professional historians trying to mark out their territory.
Some of the histories written in the Victorian period by non-professional historians are still eminently readable. Like Gibbon, they're mostly interesting as primary sources now. We've come a long way in terms of both method and, more importantly, data. That said, I would still happily recommend Leslie Stephen's History of English Thought in the Eighteenth Century.
I think "Victorian" is often a euphemism for the "Whig" progressive history which focuses on a progressive story of how middle class, male parliamentary politics came to power.